Research Interests

Our research group at the OCS Lab at IISERB has been focused on the development of new synthetic avenues towards the total synthesis of biologically-relevant organic molecules. Our group focuses on the following research themes:

• Organic synthesis via transition metal catalysis.

• Enantioselective synthesis of substituted heterocyclic natural products using C-H functionalization as the key step.

• Synthesis of natural products using transition metal catalyzed C-C bond forming reactions as the key steps.

• Synthesis of macrocyclic peptides.

• Synthesis of peptides using unnatural amino acids.

Some selected areas of our research are presented below:

(1)          In the area of organic synthesis via transition-metal catalysis, we employ two approaches to achieve our goals:

(A)  Low-valent transition-metal catalysis in C-C bond formation.

(B) High-valent transition metal catalysis in C-H and C-C bond functionalizations.

(A)          Low-valent transition metal catalysis:

In this area of research, our research group has been the first to generalize an approach towards the regioselective, indirect, C(sp3)-H arylation of enones, dienones and trienones. We have successfully employed this approach in the synthesis of several N-heterocycles and employed it twice over in the synthesis of an important building block of the drug molecule Fluvastatin. Recently, we have employed this methodology in site-selective remote functionalizations to achieve the gamma-arylations of dienones and epsilon-arylations of trienones.

(B)      High-valent transition metal catalysis in C-H and C-C bond functionalizations:

In this area of research our primary focus has been the development of new synthetic methodologies for C-C bond formation via catalyst-controlled site-specific C-H bond functionalization. The goal that we pursue in our research is to achieve a site-specific C-H functionalization in a substrate capable of undergoing multiple C-H bond functionalizations at the same time. The idea is to achieve C-H bond functionalizations which are in the near proximity of Lewis-basic heteroatom based directing groups. In the same molecule, distal C-H bond functionalization can be achieved if a heteroatom with an available non-bonded pair of electrons is conjugated to an extended pi-system. 

In addition to this, as a part of our contribution to the field of heteroatom-directed C-H functionalization, we have employed a novel methodology for the utilization of allylic alcohols as coupling partners, which is a rare and very difficult approach utilized only by a handful of research groups around the world. We have utilized this approach in the synthesis of a variety of N-heterocycles. 

We have also utilized the heteroatom-directed approach to achieve unique C-H functionalization (including nitrations and halogenations) of substrates which are very prone to SEAr reactions. 

In another approach we have achieved the C-H alkylation reactions of pi-deficient N-heterocycles and have utilized this carbene migratory insertion approach in the synthesis of a variety of fused bicyclic N-heterocycles. 

(2)             Synthesis of peptides capable of acting as anti-mycobacterial agents:

 Our group has been interested in applying a Trojan-horse approach in dealing with MDR-mycobacterium tuberculosis. To achieve this goal, our group has been developing the total synthesis of several metabolites of mycobacterium such as Mycobactin J, lasso-peptides Lariatins A & B as welll as interesting natural products such as ralsolamycin, to name a few.